BACKGROUND: The aim of this study was the longitudinal comparison of % f-PSA in patients before radical prostatectomy and after PSA relapse. Is % f-PSA a consistent tumor specific parameter or does this ratio change during untreated tumor progression? MATERIALS AND METHODS: In this study 41 out of 420 patients with untreated increasing PSA-progression (> 0.5 ng/ml) were analysed. Patients with neoadjuvant or adjuvant hormonal therapy were excluded. T-PSA were f-PSA were analyzed by Immulite DPC (Diagnostic Products Coop., CA) and Abbott Axsym (Abbott Park, Il, USA). RESULTS: Pre-operative % f-PSA ratio was 10.6% (range 4.6-22%; Std. dev.: 4.9); T-PSA concentration was 26.4 ng/ml (range 5.5-10.2 ng/ml Std. dev.: 20.3). In men with PSA relapse after radical prostatectomy % f-PSA ratio was 14.73% (range 2.2-4.5% Std. dev.: 9.7). Repeated post-operative % f-PSA measurements resulted in 12.94% f-PSA (range 2.7-3.8% Std. dev.: 9.9%) with a regression of R = 0.57. All men with pre-operative elevated % f-PSA (> 15%) had post-operative elevated % f-PSA. CONCLUSIONS: The data indicates that post-operative % f-PSA is a constant tumor specific parameter in men with untreated PSA relapse after radical prostatectomy. Post-operative % f-PSA was higher compared with pre-operative % f-PSA concentrations. No correlation with Gleason score or pathological stage was found.
